Concentration Effects on Mg Doped ZnO by Electrochemical Deposition

Nanostructures of magnesium (Mg) doped zinc oxide (ZnO) were deposited on conductive fluorine-doped tin oxide (FTO) coated glass plates by an electrochemical deposition method with different concentrations of Mg dopant and supporting electrolyte. The concentrations of magnesium chloride (MgCl₂) and potassium chloride (KCl) in the solution influence nanostructure formation, structural and optical properties of Mg doped ZnO. X-ray diffraction (XRD) measurements show that the samples prefer to grow along (002) direction. The ratio of Mg concentration to Zn concentration of 1.5 was found to be the best for the MgZnO growth at 60 °C. A stronger (002) peak intensity and better transmittance were found under these conditions as well. Scanning electron microscope (SEM) measurements show that when the concentration of KCl is lower than 0.1 M, the nanostructures have a tapered shape. When the concentration of KCl is between 0.1 M and 1 M, the nanostructures have a rod shape. When the concentration of KCl increases to 2 M, no ZnO or MgZnO was found on the substrate. UV-visible spectrophotometer measurements indicate that the samples with rod shaped nanostructures have better transmittance than the samples with taper shaped nanostructures.